What can be causing a leak on my car on the inside on front passenger side floor board under the glove box

Its your heater core

If it is clean water it is AC condensate.

But what if I haven't run my ac would it still be leaking and we noticed it mostly does it when it rains

No my 07 chevy hhr don't have no sun/moon roof it just has a regular roof and like right now there is a puddle of water on the floor board on passager side front but i felt under neath the glove box and its not even wet its just right below the front passenger side seat is where all the water is and i have no idea where its coming from cause i don't run my ac and i don't have a sun/moon roof

I had this same problem. Underneath the black plastic cowling under the windshield wiper on the passenger side there is a rubber gasket that covers the access hole where the heater and fan are located. Over time this gasket gets brittle or sags and allows water to drip down onto the heater and fan and settles in the footwell in the passenger side. I researched it online and found a video showing how to repair it. The replacement gasket part is available on line. Search under “water on passenger side” for video and “water deflector” for part. As in my case... if not taken care, it can ruin the heater and the blower resistor.

Im on my 3 rd replacement of that part. Poor design with thin plastic over heat. And wonder why it warps. Wondering why sheet metal cut to shape and siliconed into place wouldnt be a better longterm fix.....

I too am having a Leaking problem with my 2011 HHR. I have replaced that piece just under the cowel I have also had replaced windshield. It is still Leaking does anyone have suggestions as too where it could be leaking in from. It only does this when Raining. Also AC Blower was also replaced

Drain tubes are plugged.

I replaced mine with aluminum sheet cut to shape of factory gasket , and installed using pro flex silicon sealant .f looks factory and will never leak again